/*
 *  linux/include/linux/sunrpc/xprt.h
 *
 *  Declarations for the RPC transport interface.
 *
 *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#ifndef _LINUX_SUNRPC_XPRT_H
#define _LINUX_SUNRPC_XPRT_H

#include <linux/uio.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kref.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/msg_prot.h>

#ifdef __KERNEL__

#define RPC_MIN_SLOT_TABLE	(2U)
#define RPC_DEF_SLOT_TABLE	(16U)
#define RPC_MAX_SLOT_TABLE	(128U)

/*
 * This describes a timeout strategy
 */
struct rpc_timeout {
	unsigned long to_initval,	/* initial timeout */
	 to_maxval,		/* max timeout */
	 to_increment;		/* if !exponential */
	unsigned int to_retries;	/* max # of retries */
	unsigned char to_exponential;
};

enum rpc_display_format_t {
	RPC_DISPLAY_ADDR = 0,
	RPC_DISPLAY_PORT,
	RPC_DISPLAY_PROTO,
	RPC_DISPLAY_ALL,
	RPC_DISPLAY_HEX_ADDR,
	RPC_DISPLAY_HEX_PORT,
	RPC_DISPLAY_UNIVERSAL_ADDR,
	RPC_DISPLAY_NETID,
	RPC_DISPLAY_MAX,
};

struct rpc_task;
struct rpc_xprt;
struct seq_file;

/*
 * This describes a complete RPC request
 */
struct rpc_rqst {
	/*
	 * This is the user-visible part
	 */
	struct rpc_xprt *rq_xprt;	/* RPC client */
	struct xdr_buf rq_snd_buf;	/* send buffer */
	struct xdr_buf rq_rcv_buf;	/* recv buffer */

	/*
	 * This is the private part
	 */
	struct rpc_task *rq_task;	/* RPC task data */
	__be32 rq_xid;		/* request XID */
	int rq_cong;		/* has incremented xprt->cong */
	int rq_received;	/* receive completed */
	u32 rq_seqno;		/* gss seq no. used on req. */
	int rq_enc_pages_num;
	struct page **rq_enc_pages;	/* scratch pages for use by
					   gss privacy code */
	void (*rq_release_snd_buf) (struct rpc_rqst *);	/* release rq_enc_pages */
	struct list_head rq_list;

	__u32 *rq_buffer;	/* XDR encode buffer */
	size_t rq_callsize, rq_rcvsize;

	struct xdr_buf rq_private_buf;	/* The receive buffer
					 * used in the softirq.
					 */
	unsigned long rq_majortimeo;	/* major timeout alarm */
	unsigned long rq_timeout;	/* Current timeout value */
	unsigned int rq_retries;	/* # of retries */
	unsigned int rq_connect_cookie;
	/* A cookie used to track the
	   state of the transport
	   connection */

	/*
	 * Partial send handling
	 */
	u32 rq_bytes_sent;	/* Bytes we have sent */

	unsigned long rq_xtime;	/* when transmitted */
	int rq_ntrans;
};
#define rq_svec			rq_snd_buf.head
#define rq_slen			rq_snd_buf.len

struct rpc_xprt_ops {
	void (*set_buffer_size) (struct rpc_xprt * xprt, size_t sndsize,
				 size_t rcvsize);
	int (*reserve_xprt) (struct rpc_task * task);
	void (*release_xprt) (struct rpc_xprt * xprt, struct rpc_task * task);
	void (*rpcbind) (struct rpc_task * task);
	void (*set_port) (struct rpc_xprt * xprt, unsigned short port);
	void (*connect) (struct rpc_task * task);
	void *(*buf_alloc) (struct rpc_task * task, size_t size);
	void (*buf_free) (void *buffer);
	int (*send_request) (struct rpc_task * task);
	void (*set_retrans_timeout) (struct rpc_task * task);
	void (*timer) (struct rpc_task * task);
	void (*release_request) (struct rpc_task * task);
	void (*close) (struct rpc_xprt * xprt);
	void (*destroy) (struct rpc_xprt * xprt);
	void (*print_stats) (struct rpc_xprt * xprt, struct seq_file * seq);
};

struct rpc_xprt {
	struct kref kref;	/* Reference count */
	struct rpc_xprt_ops *ops;	/* transport methods */

	const struct rpc_timeout *timeout;	/* timeout parms */
	struct sockaddr_storage addr;	/* server address */
	size_t addrlen;		/* size of server address */
	int prot;		/* IP protocol */

	unsigned long cong;	/* current congestion */
	unsigned long cwnd;	/* congestion window */

	size_t max_payload;	/* largest RPC payload size,
				   in bytes */
	unsigned int tsh_size;	/* size of transport specific
				   header */

	struct rpc_wait_queue binding;	/* requests waiting on rpcbind */
	struct rpc_wait_queue sending;	/* requests waiting to send */
	struct rpc_wait_queue resend;	/* requests waiting to resend */
	struct rpc_wait_queue pending;	/* requests in flight */
	struct rpc_wait_queue backlog;	/* waiting for slot */
	struct list_head free;	/* free slots */
	struct rpc_rqst *slot;	/* slot table storage */
	unsigned int max_reqs;	/* total slots */
	unsigned long state;	/* transport state */
	unsigned char shutdown:1,	/* being shut down */
	 resvport:1;		/* use a reserved port */
	unsigned int bind_index;	/* bind function index */

	/*
	 * Connection of transports
	 */
	unsigned long connect_timeout, bind_timeout, reestablish_timeout;
	unsigned int connect_cookie;	/* A cookie that gets bumped
					   every time the transport
					   is reconnected */

	/*
	 * Disconnection of idle transports
	 */
	struct work_struct task_cleanup;
	struct timer_list timer;
	unsigned long last_used, idle_timeout;

	/*
	 * Send stuff
	 */
	spinlock_t transport_lock;	/* lock transport info */
	spinlock_t reserve_lock;	/* lock slot table */
	u32 xid;		/* Next XID value to use */
	struct rpc_task *snd_task;	/* Task blocked in send */
	struct list_head recv;

	struct {
		unsigned long bind_count,	/* total number of binds */
		 connect_count,	/* total number of connects */
		 connect_start,	/* connect start timestamp */
		 connect_time,	/* jiffies waiting for connect */
		 sends,		/* how many complete requests */
		 recvs,		/* how many complete requests */
		 bad_xids;	/* lookup_rqst didn't find XID */

		unsigned long long req_u,	/* average requests on the wire */
		 bklog_u;	/* backlog queue utilization */
	} stat;

	const char *address_strings[RPC_DISPLAY_MAX];
};

struct xprt_create {
	int ident;		/* XPRT_TRANSPORT identifier */
	struct sockaddr *srcaddr;	/* optional local address */
	struct sockaddr *dstaddr;	/* remote peer address */
	size_t addrlen;
};

struct xprt_class {
	struct list_head list;
	int ident;		/* XPRT_TRANSPORT identifier */
	struct rpc_xprt *(*setup) (struct xprt_create *);
	struct module *owner;
	char name[32];
};

/*
 * Generic internal transport functions
 */
struct rpc_xprt *xprt_create_transport(struct xprt_create *args);
void xprt_connect(struct rpc_task *task);
void xprt_reserve(struct rpc_task *task);
int xprt_reserve_xprt(struct rpc_task *task);
int xprt_reserve_xprt_cong(struct rpc_task *task);
int xprt_prepare_transmit(struct rpc_task *task);
void xprt_transmit(struct rpc_task *task);
void xprt_end_transmit(struct rpc_task *task);
int xprt_adjust_timeout(struct rpc_rqst *req);
void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
void xprt_release(struct rpc_task *task);
struct rpc_xprt *xprt_get(struct rpc_xprt *xprt);
void xprt_put(struct rpc_xprt *xprt);

static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt,
						 __be32 * p)
{
	return p + xprt->tsh_size;
}

/*
 * Transport switch helper functions
 */
int xprt_register_transport(struct xprt_class *type);
int xprt_unregister_transport(struct xprt_class *type);
void xprt_set_retrans_timeout_def(struct rpc_task *task);
void xprt_set_retrans_timeout_rtt(struct rpc_task *task);
void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
void xprt_write_space(struct rpc_xprt *xprt);
void xprt_update_rtt(struct rpc_task *task);
void xprt_adjust_cwnd(struct rpc_task *task, int result);
struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
void xprt_complete_rqst(struct rpc_task *task, int copied);
void xprt_release_rqst_cong(struct rpc_task *task);
void xprt_disconnect_done(struct rpc_xprt *xprt);
void xprt_force_disconnect(struct rpc_xprt *xprt);
void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);

/*
 * Reserved bit positions in xprt->state
 */
#define XPRT_LOCKED		(0)
#define XPRT_CONNECTED		(1)
#define XPRT_CONNECTING		(2)
#define XPRT_CLOSE_WAIT		(3)
#define XPRT_BOUND		(4)
#define XPRT_BINDING		(5)
#define XPRT_CLOSING		(6)

static inline void xprt_set_connected(struct rpc_xprt *xprt)
{
	set_bit(XPRT_CONNECTED, &xprt->state);
}

static inline void xprt_clear_connected(struct rpc_xprt *xprt)
{
	clear_bit(XPRT_CONNECTED, &xprt->state);
}

static inline int xprt_connected(struct rpc_xprt *xprt)
{
	return test_bit(XPRT_CONNECTED, &xprt->state);
}

static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
{
	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
}

static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
{
	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
}

static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
{
	smp_mb__before_clear_bit();
	clear_bit(XPRT_CONNECTING, &xprt->state);
	smp_mb__after_clear_bit();
}

static inline int xprt_connecting(struct rpc_xprt *xprt)
{
	return test_bit(XPRT_CONNECTING, &xprt->state);
}

static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
{
	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
}

static inline void xprt_set_bound(struct rpc_xprt *xprt)
{
	test_and_set_bit(XPRT_BOUND, &xprt->state);
}

static inline int xprt_bound(struct rpc_xprt *xprt)
{
	return test_bit(XPRT_BOUND, &xprt->state);
}

static inline void xprt_clear_bound(struct rpc_xprt *xprt)
{
	clear_bit(XPRT_BOUND, &xprt->state);
}

static inline void xprt_clear_binding(struct rpc_xprt *xprt)
{
	smp_mb__before_clear_bit();
	clear_bit(XPRT_BINDING, &xprt->state);
	smp_mb__after_clear_bit();
}

static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
{
	return test_and_set_bit(XPRT_BINDING, &xprt->state);
}

#endif /* __KERNEL__ */

#endif /* _LINUX_SUNRPC_XPRT_H */
